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Ibañez-Escribano A, Gomez-Muñoz MT, Mateo M, Fonseca-Berzal C, Gomez-Lucia E, Perez RG, Alunda JM, Carrion J. Microbial Matryoshka: Addressing the Relationship between Pathogenic Flagellated Protozoans and Their RNA Viral Endosymbionts (Family Totiviridae). Vet Sci 2024; 11:321. [PMID: 39058005 PMCID: PMC11281412 DOI: 10.3390/vetsci11070321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Revised: 07/12/2024] [Accepted: 07/14/2024] [Indexed: 07/28/2024] Open
Abstract
Three genera of viruses of the family Totiviridae establish endosymbiotic associations with flagellated protozoa responsible for parasitic diseases of great impact in the context of One Health. Giardiavirus, Trichomonasvirus, and Leishmaniavirus infect the protozoa Giardia sp., Trichomonas vaginalis, and Leishmania sp., respectively. In the present work, we review the characteristics of the endosymbiotic relationships established, the advantages, and the consequences caused in mammalian hosts. Among the common characteristics of these double-stranded RNA viruses are that they do not integrate into the host genome, do not follow a lytic cycle, and do not cause cytopathic effects. However, in cases of endosymbiosis between Leishmaniavirus and Leishmania species from the Americas, and between Trichomonasvirus and Trichomonas vaginalis, it seems that it can alter their virulence (degree of pathogenicity). In a mammalian host, due to TLR3 activation of immune cells upon the recognition of viral RNA, uncontrolled inflammatory signaling responses are triggered, increasing pathological damage and the risk of failure of conventional standard treatment. Endosymbiosis with Giardiavirus can cause the loss of intestinal adherence of the protozoan, resulting in a benign disease. The current knowledge about viruses infecting flagellated protozoans is still fragmentary, and more research is required to unravel the intricacies of this three-way relationship. We need to develop early and effective diagnostic methods for further development in the field of translational medicine. Taking advantage of promising biotechnological advances, the aim is to develop ad hoc therapeutic strategies that focus not only on the disease-causing protozoan but also on the virus.
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Affiliation(s)
- Alexandra Ibañez-Escribano
- Department of Microbiology and Parasitology, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain; (A.I.-E.); (M.M.); (C.F.-B.)
| | - Maria Teresa Gomez-Muñoz
- ICPVet Research Group, Department of Animal Health, Faculty of Veterinary Medicine, Complutense University of Madrid, 28040 Madrid, Spain; (M.T.G.-M.); (R.G.P.); (J.M.A.)
- Research Institute Hospital 12 de Octubre, 28041 Madrid, Spain
| | - Marta Mateo
- Department of Microbiology and Parasitology, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain; (A.I.-E.); (M.M.); (C.F.-B.)
- ICPVet Research Group, Department of Animal Health, Faculty of Veterinary Medicine, Complutense University of Madrid, 28040 Madrid, Spain; (M.T.G.-M.); (R.G.P.); (J.M.A.)
- Research Institute Hospital 12 de Octubre, 28041 Madrid, Spain
| | - Cristina Fonseca-Berzal
- Department of Microbiology and Parasitology, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain; (A.I.-E.); (M.M.); (C.F.-B.)
| | - Esperanza Gomez-Lucia
- Animal Viruses Research Group, Department of Animal Health, Faculty of Veterinary Medicine, Complutense University of Madrid, 28040 Madrid, Spain;
| | - Raquel Garcia Perez
- ICPVet Research Group, Department of Animal Health, Faculty of Veterinary Medicine, Complutense University of Madrid, 28040 Madrid, Spain; (M.T.G.-M.); (R.G.P.); (J.M.A.)
| | - Jose M. Alunda
- ICPVet Research Group, Department of Animal Health, Faculty of Veterinary Medicine, Complutense University of Madrid, 28040 Madrid, Spain; (M.T.G.-M.); (R.G.P.); (J.M.A.)
- Research Institute Hospital 12 de Octubre, 28041 Madrid, Spain
| | - Javier Carrion
- ICPVet Research Group, Department of Animal Health, Faculty of Veterinary Medicine, Complutense University of Madrid, 28040 Madrid, Spain; (M.T.G.-M.); (R.G.P.); (J.M.A.)
- Research Institute Hospital 12 de Octubre, 28041 Madrid, Spain
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Zhang K, Shen H, Wang Y, Shen H, Zhang C, Zou X, Yu Y, Tian X, Wang Y. Identification of End-Binding 1 Protein as Novel α-4 Giardin-Binding Partners in Giardia lamblia Trophozoites. Acta Parasitol 2024; 69:505-513. [PMID: 38206477 PMCID: PMC11001682 DOI: 10.1007/s11686-023-00774-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 12/04/2023] [Indexed: 01/12/2024]
Abstract
BACKGROUND Giardia lamblia (syn. G. intestinalis, G. duodenalis) is a primitive opportunistic protozoon, and one of the earliest differentiated eukaryotes. Despite its primitive nature, G. lamblia has a sophisticated cytoskeleton system, which is closely related to its proliferation and pathogenicity. Meanwhile, α giardin is a G. lamblia-specific cytoskeleton protein, which belongs to the annexin superfamily. Interestingly, G. lamblia has 21 annexin-like α giardins, i.e., more than higher eukaryotes. The functional differences among α giardin members are not fully understood. METHODS We took α-4 giardin, a member of α giardin family, as a research object. A morpholino-mediated knockdown experiment was performed to identify the effect of α-4 giardin on G. lamblia trophozoites biological traits. A yeast two-hybrid cDNA library of G. lamblia strain C2 trophozoites was screened for interaction partners of α-4 giardin. Co-immunoprecipitation and fluorescent colocalization confirmed the relationship between G. lamblia EB1 (gEB1) and α-4 giardin. RESULTS α-4 Giardin could inhibit the proliferation and adhesion of G. lamblia trophozoites. In addition, it interacted with G. lamblia EB1 (gEB1). CONCLUSIONS α-4 Giardin was involved in proliferation and adhesion in G. lamblia trophozoites, and EB1, a crucial roles in mitosis, was an interacting partner of α-4 giardin.
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Affiliation(s)
- Kaiyue Zhang
- College of Life Sciences, North China University of Science and Technology, Tangshan, 063000, China
| | - Hai'e Shen
- College of Life Sciences, North China University of Science and Technology, Tangshan, 063000, China
| | - Yi Wang
- Department of Clinical Laboratory, North China University of Science and Technology Affiliated Hospital, Tangshan, 063000, China
| | - Hailin Shen
- The Second Hospital of Tangshan, Tangshan, 063000, China
| | - Chenshuo Zhang
- College of Life Sciences, North China University of Science and Technology, Tangshan, 063000, China
| | - Xu Zou
- College of Life Sciences, North China University of Science and Technology, Tangshan, 063000, China
| | - Yuan Yu
- College of Life Sciences, North China University of Science and Technology, Tangshan, 063000, China.
| | - Xifeng Tian
- College of Basic Medical Sciences, North China University of Science and Technology, Tangshan, 063000, China
| | - Yang Wang
- College of Life Sciences, North China University of Science and Technology, Tangshan, 063000, China.
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Nosala C, Hagen KD, Guest SL, Hilton NA, Müller A, Laue M, Klotz C, Aebischer A, Dawson SC. Dynamic ventral disc contraction is necessary for Giardia attachment and host pathology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.04.547600. [PMID: 37461436 PMCID: PMC10349954 DOI: 10.1101/2023.07.04.547600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Giardia lamblia is a common parasitic protist that infects the small intestine and causes giardiasis, resulting in diarrhea, vomiting, weight loss, and malabsorption. Giardiasis leads to cellular damage, including loss of microvilli, disruption of tight junctions, impaired barrier function, enzyme inhibition, malabsorption, and apoptosis. In the host, motile Giardia trophozoites attach to the duodenal microvilli using a unique microtubule organelle called the ventral disc. Despite early observations of disc-shaped depressions in microvilli after parasite detachment, little is known about disc-mediated attachment mechanisms and there little direct evidence showing that parasite attachment causes cellular damage. However, advancements in in vitro organoid models of infection and genetic tools have opened new possibilities for studying molecular mechanisms of attachment and the impact of attachment on the host. Through high-resolution live imaging and a novel disc mutant, we provide direct evidence for disc contraction during attachment, resolving the long-standing controversy of its existence. Specifically, we identify three types of disc movements that characterize contraction, which in combination result in a decrease in disc diameter and volume. Additionally, we investigate the consequences of attachment and disc contractility using an attachment mutant that has abnormal disc architecture. In a human organoid model, we demonstrate that this mutant has a limited ability to break down the epithelial barrier as compared to wild type. Based on this direct evidence, we propose a model of attachment that incorporates disc contraction to generates the forces required for the observed "grasping" of trophozoites on the host epithelium. Overall, this work highlights the importance of disc contractility in establishing and maintaining parasite attachment, leading to intestinal barrier breakdown.
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Influence of Selected Factors on the Survival Assessment and Detection of Giardia intestinalis DNA in Axenic Culture. Pathogens 2023; 12:pathogens12020316. [PMID: 36839588 PMCID: PMC9968169 DOI: 10.3390/pathogens12020316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023] Open
Abstract
Giardia intestinalis is one of the most common food-borne protozoa. The sensitivity of pathogens to physical and chemical factors is the basis for developing measures to reduce the incidence of the population. Several methods are available to detect the presence of G. intestinalis. The study determines the influence of 22 selected factors on the survival assessment and detection of G. intestinalis DNA in trophozoites axenically cultured. The influence of a given factor on the test result was observed in the case of 17 factors (77.3%) in the microscopic method, while only in the case of 3 (13.6%) substances in the real-time PCR method. Prevention of G. intestinalis infections, e.g., by ensuring food and water safety, is a crucial issue affecting public health. The experiment was conducted on trophozoites as the first approach. It is necessary to continue research and observe the epidemiological situation. In future studies, the impact of the studied factors on the survival assessment and detection of Giardia intestinalis DNA in axenically cultured cysts should be determined.
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Onursal A, Icgen B. Wastewater treatment plants discharges disseminated more Giardia than Cryptosporidium. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2023; 95:e10839. [PMID: 36751137 DOI: 10.1002/wer.10839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 01/16/2023] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
Parasitic protozoa Giardia intestinalis and Cryptosporidium parvum are causative agents for giardiasis and cryptosporidiosis, respectively. These infections are mostly associated with waterborne diseases. The discharges from wastewater treatment plants (WWTPs) that reach surface waters cause waterborne transmission because there are no regulations for monitoring these protozoa. This emphasizes how crucial the removal capacities of WWTPs to prevent the spread of infectious parasitic pathogens. For this reason, in this study, five different types of WWTPs including conventional activated sludge (CAS), biological nutrient removal (BNR), sequencing batch reactor (SBR), membrane bioreactor (MBR), and WWTP with coagulation-flocculation and UV disinfection (CoFlUV) units were investigated over a year, seasonally in terms of their G. intestinalis and C. parvum removal capacities. The seasonal abundances of these protozoa-specific genes in both the influents and effluents of each WWTP were determined by qPCR. The reduction of protozoan rDNA copies in the effluent wastewater samples compared with the influent wastewater samples was assessed as log10 reduction values (LRVs). LRVs >3 were reachable for C. parvum in all types of WWTPs tested. However, only LRVs 1-2 were reachable for G. intestinalis in CAS, SBR, CoFlUV, and MBR. Significant seasonal variations were just observed in SBR and CAS for G. intestinalis and C. parvum (p < 0.05), respectively. The findings depicted that WWTPs tested disseminated more giardiasis causative agents than cryptosporidiosis. Therefore, G. intestinalis needs to be monitored in WWTPs' discharges to reduce any potential damage of this parasite to public health. PRACTITIONER POINTS: Removal of G. intestinalis and C. parvum in WWTPs was affected by the process. LRV 2.92 was the highest LRV achieved for G. intestinalis. LRV >3 was reachable for C. parvum. WWTPs discharges disseminated more G. intestinalis than C. parvum. WWTPs effluents should be monitored in terms of G. intestinalis.
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Affiliation(s)
- Asli Onursal
- Department of Environmental Engineering, Middle East Technical University, Ankara, Turkey
| | - Bulent Icgen
- Department of Environmental Engineering, Middle East Technical University, Ankara, Turkey
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Steele-Ogus MC, Obenaus AM, Sniadecki NJ, Paredez AR. Disc and Actin Associated Protein 1 influences attachment in the intestinal parasite Giardia lamblia. PLoS Pathog 2022; 18:e1010433. [PMID: 35333908 PMCID: PMC8986099 DOI: 10.1371/journal.ppat.1010433] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 04/06/2022] [Accepted: 03/10/2022] [Indexed: 02/01/2023] Open
Abstract
The deep-branching eukaryote Giardia lamblia is an extracellular parasite that attaches to the host intestine via a microtubule-based structure called the ventral disc. Control of attachment is mediated in part by the movement of two regions of the ventral disc that either permit or exclude the passage of fluid under the disc. Several known disc-associated proteins (DAPs) contribute to disc structure and function, but no force-generating protein has been identified among them. We recently identified several Giardia actin (GlActin) interacting proteins at the ventral disc, which could potentially employ actin polymerization for force generation and disc conformational changes. One of these proteins, Disc and Actin Associated Protein 1 (DAAP1), is highly enriched at the two regions of the disc previously shown to be important for fluid flow during attachment. In this study, we investigate the role of both GlActin and DAAP1 in ventral disc morphology and function. We confirmed interaction between GlActin and DAAP1 through coimmunoprecipitation, and used immunofluorescence to localize both proteins throughout the cell cycle and during trophozoite attachment. Similar to other DAPs, the association of DAAP1 with the disc is stable, except during cell division when the disc disassembles. Depletion of GlActin by translation-blocking antisense morpholinos resulted in both impaired attachment and defects in the ventral disc, indicating that GlActin contributes to disc-mediated attachment. Depletion of DAAP1 through CRISPR interference resulted in intact discs but impaired attachment, gating, and flow under the disc. As attachment is essential for infection, elucidation of these and other molecular mediators is a promising area for development of new therapeutics against a ubiquitous parasite.
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Affiliation(s)
- Melissa C. Steele-Ogus
- Department of Biology, University of Washington, Seattle, Washington, United States of America
| | - Ava M. Obenaus
- Department of Mechanical Engineering, University of Washington, Seattle, Washington, United States of America
| | - Nathan J. Sniadecki
- Department of Mechanical Engineering, University of Washington, Seattle, Washington, United States of America
| | - Alexander R. Paredez
- Department of Biology, University of Washington, Seattle, Washington, United States of America
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Alvarado ME, Chaparro-Gutiérrez JJ, Calvo EP, Prada LF, Wasserman M. Activity of the Giardia intestinalis proteasome during encystation and its connection with the expression of the cyst wall protein 1 (CWP1). Acta Trop 2022; 225:106183. [PMID: 34627761 DOI: 10.1016/j.actatropica.2021.106183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 09/27/2021] [Accepted: 09/29/2021] [Indexed: 11/01/2022]
Abstract
Giardia is a parasite whose life cycle is composed of two stages: replicative trophozoites, responsible for the symptoms of the disease, and infective cysts, resistant to adverse environments outside of hosts. Proteasomes are multicatalytic peptidase complexes responsible for the specific degradation of proteins in eukaryotic cells. This study assessed the proteasome activity in the trophozoite and during encystation. Strong activation of the proteasome was observed during the differentiation of trophozoites into cysts, reaching its maximum level 24 h after the stimulus. We also found that the Giardia proteasome presents unusual characteristics related to higher eukaryotic proteasomes, making it an eventual therapeutic target. Here we tested the effects on the synthesis of a cyst wall protein by chemical inactivation of the proteasome and by overexpression or partial inhibition of the deubiquitinating protein RPN11 in transfected cells. Moreover, an analysis of the intracellular localization of RPN11 (an integral part of the proteasome regulatory particle) revealed major changes associated with the differentiation of trophozoites into cysts. This evidence further supports the important role of the proteasome in Giardia encystation.
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Abstract
Purpose of review Here, we review recent progress made on the genetic characterization of Giardia duodenalis assemblages and their relationship with virulence. We also discuss the implications of virulence factors in the pathogenesis of giardiasis, and advances in the development of vaccines and drugs based on knowledge of virulence markers. Recent findings The use of transcriptomic and proteomic technologies as well as whole genome sequencing (WGS) from single cysts has allowed the assembly of the draft genome sequences for assemblages C and D of G. duodenalis. These findings, along with the published genomes for assemblages A, B, and E, have allowed comparative genomic investigations. In addition, the use of these methodologies for the characterization of the secretomes of trophozoite-epithelial cell interactions for assemblages A/B has led to the identification of virulence markers including energy metabolism enzymes, proteinases, high-cysteine membrane proteins (HCMPs), and variant surface proteins (VSPs). Recently, some drugs and vaccines, targeting virulence factors have been developed, offering possible alternatives to current treatment and prevention options against giardiasis. Summary Among the nine recognized species of Giardia, G. duodenalis stands out because of its broad spectrum of hosts and its socio-economic importance. This species comprises eight genetic assemblages (A to H), of which A and B are zoonotic, and the other assemblages have narrow host specificities. Assemblages A and B may be considered as the most virulent ones, but the existence of asymptomatic carriers and considerable genetic variability within and among these assemblages hampers the definition of common virulence factors. The attachment of Giardia trophozoites to epithelial cells and structural cytoskeleton components of the adhesive disk, such as giardins or tubulins, is proposed to play key roles, but toxins have not yet been precisely defined. However, recent transcriptomic and proteomic analyses of the secretomes of trophozoites representing assemblages A and B and interacting with particular epithelial cell lines have defined a series of virulence factors, including glycolytic (e.g., enolase) and arginolytic (e.g., arginine deiminase) enzymes, cysteine proteases (e.g., giardipain-1) and VSPs (e.g., VSP9B10A). Other factors, such as HCMPs and tenascins, have been consistently found to be excreted/secreted, but their role(s) in the pathogenesis of giardiasis has not yet been elucidated. Interestingly, recent investigations of single cysts representing assemblages C and D using advanced sequencing and informatic methods have suggested that the transcription/expression profiles of virulence factors vary both within and between assemblages, thus assemblage-specific molecules might allow adaptation to the microenvironment within the host. Importantly, some drugs active against cysteine-rich proteins of Giardia, including giardipain-1, VSPs and arginine deiminase, have been shown to be targeted by cysteine-modifying compounds as disulfiram, L-canavanin and allicin. On the other hand, VSPs are presently considered as key vaccine candidates because they induce protection against Giardia in rodents and dogs. Overall, this review reveals that much more work is needed to identify, characterize, and understand the roles of virulence factors in Giardia and to assess their validity as drug and vaccine targets. Clear, advanced omics and informatic tools should assist in this future endeavor, with a focus on targeting virulence factors that are common and/or unique to distinct assemblages to develop new and effective interventions against Giardia.
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Emery-Corbin SJ, Hamey JJ, Ansell BRE, Balan B, Tichkule S, Stroehlein AJ, Cooper C, McInerney BV, Hediyeh-Zadeh S, Vuong D, Crombie A, Lacey E, Davis MJ, Wilkins MR, Bahlo M, Svärd SG, Gasser RB, Jex AR. Eukaryote-Conserved Methylarginine Is Absent in Diplomonads and Functionally Compensated in Giardia. Mol Biol Evol 2021; 37:3525-3549. [PMID: 32702104 PMCID: PMC7743719 DOI: 10.1093/molbev/msaa186] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Methylation is a common posttranslational modification of arginine and lysine in eukaryotic proteins. Methylproteomes are best characterized for higher eukaryotes, where they are functionally expanded and evolved complex regulation. However, this is not the case for protist species evolved from the earliest eukaryotic lineages. Here, we integrated bioinformatic, proteomic, and drug-screening data sets to comprehensively explore the methylproteome of Giardia duodenalis-a deeply branching parasitic protist. We demonstrate that Giardia and related diplomonads lack arginine-methyltransferases and have remodeled conserved RGG/RG motifs targeted by these enzymes. We also provide experimental evidence for methylarginine absence in proteomes of Giardia but readily detect methyllysine. We bioinformatically infer 11 lysine-methyltransferases in Giardia, including highly diverged Su(var)3-9, Enhancer-of-zeste and Trithorax proteins with reduced domain architectures, and novel annotations demonstrating conserved methyllysine regulation of eukaryotic elongation factor 1 alpha. Using mass spectrometry, we identify more than 200 methyllysine sites in Giardia, including in species-specific gene families involved in cytoskeletal regulation, enriched in coiled-coil features. Finally, we use known methylation inhibitors to show that methylation plays key roles in replication and cyst formation in this parasite. This study highlights reduced methylation enzymes, sites, and functions early in eukaryote evolution, including absent methylarginine networks in the Diplomonadida. These results challenge the view that arginine methylation is eukaryote conserved and demonstrate that functional compensation of methylarginine was possible preceding expansion and diversification of these key networks in higher eukaryotes.
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Affiliation(s)
- Samantha J Emery-Corbin
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Joshua J Hamey
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Brendan R E Ansell
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Balu Balan
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia.,Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Swapnil Tichkule
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Andreas J Stroehlein
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Crystal Cooper
- Central Analytical Research Facility (CARF), Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, Australia
| | - Bernie V McInerney
- Australian Proteome Analysis Facility (APAF), Macquarie University, North Ryde, NSW, Australia
| | - Soroor Hediyeh-Zadeh
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia.,Bioinformatics Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
| | - Daniel Vuong
- Microbial Screening Technologies, Smithfield, NSW, Australia
| | - Andrew Crombie
- Microbial Screening Technologies, Smithfield, NSW, Australia
| | - Ernest Lacey
- Microbial Screening Technologies, Smithfield, NSW, Australia.,Chemistry and Biomolecular Sciences, Faculty of Science, Macquarie University, North Ryde, NSW, Australia
| | - Melissa J Davis
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia.,Bioinformatics Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
| | - Marc R Wilkins
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Melanie Bahlo
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Staffan G Svärd
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Robin B Gasser
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Aaron R Jex
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia.,Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, Australia
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Giardia intestinalis coiled-coil cytolinker protein 259 interacts with actin and tubulin. Parasitol Res 2021; 120:1067-1076. [PMID: 33515065 DOI: 10.1007/s00436-021-07062-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 01/18/2021] [Indexed: 01/06/2023]
Abstract
Giardia intestinalis is a human parasite that causes a diarrheal disease in developing countries. G. intestinalis has a cytoskeleton (CSK) composed of microtubules and microfilaments, and the Giardia genome does not code for the canonical CSK-binding proteins described in other eukaryotic cells. To identify candidate actin and tubulin cross-linking proteins, we performed a BLAST analysis of the Giardia genome using a spectraplakins consensus sequence as a query. Based on the highest BLAST score, we selected a 259-kDa sequence designated as a cytoskeleton linker protein (CLP259). The sequence was cloned in three fragments and characterized by immunoprecipitation, confocal microscopy, and mass spectrometry (MS). CLP259 was located in the cytoplasm in the form of clusters of thick rods and colocalized with actin at numerous sites and with tubulin in the median body. Immunoprecipitation followed by mass spectrometry revealed that CLP259 interacts with structural proteins such as giardins, SALP-1, axonemal, and eight coiled-coils. The vesicular traffic proteins detected were Mu adaptin, Vacuolar ATP synthase subunit B, Bip, Sec61 alpha, NSF, AP complex subunit beta, and dynamin. These results indicate that CLP259 in trophozoites is a CSK linker protein for actin and tubulin and could act as a scaffold protein driving vesicular traffic.
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11
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Nosala C, Hagen KD, Hilton N, Chase TM, Jones K, Loudermilk R, Nguyen K, Dawson SC. Disc-associated proteins mediate the unusual hyperstability of the ventral disc in Giardia lamblia. J Cell Sci 2020; 133:jcs.227355. [PMID: 32661087 DOI: 10.1242/jcs.227355] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 06/29/2020] [Indexed: 12/26/2022] Open
Abstract
Giardia lamblia, a widespread parasitic protozoan, attaches to the host gastrointestinal epithelium by using the ventral disc, a complex microtubule (MT) organelle. The 'cup-like' disc is formed by a spiral MT array that scaffolds numerous disc-associated proteins (DAPs) and higher-order protein complexes. In interphase, the disc is hyperstable and has limited MT dynamics; however, it remains unclear how DAPs confer these properties. To investigate mechanisms of hyperstability, we confirmed the disc-specific localization of over 50 new DAPs identified by using both a disc proteome and an ongoing GFP localization screen. DAPs localize to specific disc regions and many lack similarity to known proteins. By screening 14 CRISPRi-mediated DAP knockdown (KD) strains for defects in hyperstability and MT dynamics, we identified two strains - DAP5188KD and DAP6751KD -with discs that dissociate following high-salt fractionation. Discs in the DAP5188KD strain were also sensitive to treatment with the MT-polymerization inhibitor nocodazole. Thus, we confirm here that at least two of the 87 known DAPs confer hyperstable properties to the disc MTs, and we anticipate that other DAPs contribute to disc MT stability, nucleation and assembly.
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Affiliation(s)
- Christopher Nosala
- Department of Microbiology and Molecular Genetics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Kari D Hagen
- Department of Microbiology and Molecular Genetics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Nicholas Hilton
- Department of Microbiology and Molecular Genetics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Tiffany M Chase
- Department of Microbiology and Molecular Genetics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Kelci Jones
- Department of Microbiology and Molecular Genetics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Rita Loudermilk
- Department of Microbiology and Molecular Genetics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Kristofer Nguyen
- Department of Microbiology and Molecular Genetics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Scott C Dawson
- Department of Microbiology and Molecular Genetics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
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12
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Xu F, Jiménez-González A, Einarsson E, Ástvaldsson Á, Peirasmaki D, Eckmann L, Andersson JO, Svärd SG, Jerlström-Hultqvist J. The compact genome of Giardia muris reveals important steps in the evolution of intestinal protozoan parasites. Microb Genom 2020; 6:mgen000402. [PMID: 32618561 PMCID: PMC7641422 DOI: 10.1099/mgen.0.000402] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 06/16/2020] [Indexed: 01/05/2023] Open
Abstract
Diplomonad parasites of the genus Giardia have adapted to colonizing different hosts, most notably the intestinal tract of mammals. The human-pathogenic Giardia species, Giardia intestinalis, has been extensively studied at the genome and gene expression level, but no such information is available for other Giardia species. Comparative data would be particularly valuable for Giardia muris, which colonizes mice and is commonly used as a prototypic in vivo model for investigating host responses to intestinal parasitic infection. Here we report the draft-genome of G. muris. We discovered a highly streamlined genome, amongst the most densely encoded ever described for a nuclear eukaryotic genome. G. muris and G. intestinalis share many known or predicted virulence factors, including cysteine proteases and a large repertoire of cysteine-rich surface proteins involved in antigenic variation. Different to G. intestinalis, G. muris maintains tandem arrays of pseudogenized surface antigens at the telomeres, whereas intact surface antigens are present centrally in the chromosomes. The two classes of surface antigens engage in genetic exchange. Reconstruction of metabolic pathways from the G. muris genome suggest significant metabolic differences to G. intestinalis. Additionally, G. muris encodes proteins that might be used to modulate the prokaryotic microbiota. The responsible genes have been introduced in the Giardia genus via lateral gene transfer from prokaryotic sources. Our findings point to important evolutionary steps in the Giardia genus as it adapted to different hosts and it provides a powerful foundation for mechanistic exploration of host-pathogen interaction in the G. muris-mouse pathosystem.
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Affiliation(s)
- Feifei Xu
- Department of Cell and Molecular Biology, BMC, Box 596, Uppsala Universitet, SE-751 24 Uppsala, Sweden
| | | | - Elin Einarsson
- Department of Cell and Molecular Biology, BMC, Box 596, Uppsala Universitet, SE-751 24 Uppsala, Sweden
- Present address: Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Ásgeir Ástvaldsson
- Department of Cell and Molecular Biology, BMC, Box 596, Uppsala Universitet, SE-751 24 Uppsala, Sweden
- Present address: Department of Microbiology, National Veterinary Institute, Uppsala, Sweden
| | - Dimitra Peirasmaki
- Department of Cell and Molecular Biology, BMC, Box 596, Uppsala Universitet, SE-751 24 Uppsala, Sweden
- Present address: Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden
| | - Lars Eckmann
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Jan O. Andersson
- Department of Cell and Molecular Biology, BMC, Box 596, Uppsala Universitet, SE-751 24 Uppsala, Sweden
| | - Staffan G. Svärd
- Department of Cell and Molecular Biology, BMC, Box 596, Uppsala Universitet, SE-751 24 Uppsala, Sweden
| | - Jon Jerlström-Hultqvist
- Department of Cell and Molecular Biology, BMC, Box 596, Uppsala Universitet, SE-751 24 Uppsala, Sweden
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13
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Hagen KD, McInally SG, Hilton ND, Dawson SC. Microtubule organelles in Giardia. ADVANCES IN PARASITOLOGY 2020; 107:25-96. [PMID: 32122531 DOI: 10.1016/bs.apar.2019.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Giardia lamblia is a widespread parasitic protist with a complex MT cytoskeleton that is critical for motility, attachment, mitosis and cell division, and transitions between its two life cycle stages-the infectious cyst and flagellated trophozoite. Giardia trophozoites have both highly dynamic and highly stable MT organelles, including the ventral disc, eight flagella, the median body and the funis. The ventral disc, an elaborate MT organelle, is essential for the parasite's attachment to the intestinal villi to avoid peristalsis. Giardia's four flagellar pairs enable swimming motility and may also promote attachment. They are maintained at different equilibrium lengths and are distinguished by their long cytoplasmic regions and novel extra-axonemal structures. The functions of the median body and funis, MT organelles unique to Giardia, remain less understood. In addition to conserved MT-associated proteins, the genome is enriched in ankyrins, NEKs, and novel hypothetical proteins that also associate with the MT cytoskeleton. High-resolution ultrastructural imaging and a current inventory of more than 300 proteins associated with Giardia's MT cytoskeleton lay the groundwork for future mechanistic analyses of parasite attachment to the host, motility, cell division, and encystation/excystation. Giardia's unique MT organelles exemplify the capacity of MT polymers to generate intricate structures that are diverse in both form and function. Thus, beyond its relevance to pathogenesis, the study of Giardia's MT cytoskeleton informs basic cytoskeletal biology and cellular evolution. With the availability of new molecular genetic tools to disrupt gene function, we anticipate a new era of cytoskeletal discovery in Giardia.
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Affiliation(s)
- Kari D Hagen
- Department of Microbiology and Molecular Genetics, UC Davis, Davis, CA, United States
| | - Shane G McInally
- Department of Microbiology and Molecular Genetics, UC Davis, Davis, CA, United States
| | - Nicholas D Hilton
- Department of Microbiology and Molecular Genetics, UC Davis, Davis, CA, United States
| | - Scott C Dawson
- Department of Microbiology and Molecular Genetics, UC Davis, Davis, CA, United States.
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14
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Jex AR, Svärd S, Hagen KD, Starcevich H, Emery-Corbin SJ, Balan B, Nosala C, Dawson SC. Recent advances in functional research in Giardia intestinalis. ADVANCES IN PARASITOLOGY 2020; 107:97-137. [PMID: 32122532 PMCID: PMC7878119 DOI: 10.1016/bs.apar.2019.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This review considers current advances in tools to investigate the functional biology of Giardia, it's coding and non-coding genes, features and cellular and molecular biology. We consider major gaps in current knowledge of the parasite and discuss the present state-of-the-art in its in vivo and in vitro cultivation. Advances in in silico tools, including for the modelling non-coding RNAs and genomic elements, as well as detailed exploration of coding genes through inferred homology to model organisms, have provided significant, primary level insight. Improved methods to model the three-dimensional structure of proteins offer new insights into their function, and binding interactions with ligands, other proteins or precursor drugs, and offer substantial opportunities to prioritise proteins for further study and experimentation. These approaches can be supplemented by the growing and highly accessible arsenal of systems-based methods now being applied to Giardia, led by genomic, transcriptomic and proteomic methods, but rapidly incorporating advanced tools for detection of real-time transcription, evaluation of chromatin states and direct measurement of macromolecular complexes. Methods to directly interrogate and perturb gene function have made major leaps in recent years, with CRISPr-interference now available. These approaches, coupled with protein over-expression, fluorescent labelling and in vitro and in vivo imaging, are set to revolutionize the field and herald an exciting time during which the field may finally realise Giardia's long proposed potential as a model parasite and eukaryote.
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Affiliation(s)
- Aaron R Jex
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia; Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, Australia.
| | - Staffan Svärd
- Centre for Biomedicine, Uppsala University, Uppsala, Sweden
| | - Kari D Hagen
- College of Biological Sciences, University of California-Davis, Davis, CA, United States
| | - Hannah Starcevich
- College of Biological Sciences, University of California-Davis, Davis, CA, United States
| | - Samantha J Emery-Corbin
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia
| | - Balu Balan
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia
| | - Chris Nosala
- College of Biological Sciences, University of California-Davis, Davis, CA, United States
| | - Scott C Dawson
- College of Biological Sciences, University of California-Davis, Davis, CA, United States
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15
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Emery-Corbin SJ, Grüttner J, Svärd S. Transcriptomic and proteomic analyses of Giardia intestinalis: Intestinal epithelial cell interactions. ADVANCES IN PARASITOLOGY 2019; 107:139-171. [PMID: 32122528 DOI: 10.1016/bs.apar.2019.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Giardia intestinalis is a unicellular protozoan parasite that infects the small intestines of humans and animals. Giardiasis, the disease caused by the parasite, occurs globally across socioeconomic boundaries but is mainly endemic in developing countries and particularly within young children, where pronounced effects manifests in a failure to thrive condition. The molecular pathogenesis of Giardia has been studied using in vitro models of human and rat intestinal epithelial cells (IECs) and parasites from the two major human genotypes or assemblages (A and B). High-quality, genome sequencing of representative isolates from assemblages A (WB) and B (GS) has enabled exploration of these host-parasite models using 'omics' technologies, allowing deep and quantitative analyses of global gene expression changes in IECs and parasites during their interactions, cross-talk and competition. These include a major up-regulation of immune-related genes in the IECs early after the start of interactions, as well as competition between host cells and parasites for nutrients like sugars, amino acids and lipids, which is also reflected in their secretome interactions. Unique parasite proteins dominate these interactions, with many major up-regulated genes being either hypothetical proteins or members of Giardia-specific gene families like the high-cysteine-rich membrane proteins (HCMPs), variable surface proteins (VSPs), alpha-giardins and cysteine proteases. Furthermore, these proteins also dominate in the secretomes, suggesting that they are important virulence factors in Giardia and crucial molecular effectors at the host-parasite interface.
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Affiliation(s)
- Samantha J Emery-Corbin
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia
| | - Jana Grüttner
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Staffan Svärd
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
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16
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Meningher T, Boleslavsky D, Barshack I, Tabibian-Keissar H, Kohen R, Gur-Wahnon D, Ben-Dov IZ, Sidi Y, Avni D, Schwartz E. Giardia lamblia miRNAs as a new diagnostic tool for human giardiasis. PLoS Negl Trop Dis 2019; 13:e0007398. [PMID: 31206518 PMCID: PMC6597124 DOI: 10.1371/journal.pntd.0007398] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 06/27/2019] [Accepted: 04/16/2019] [Indexed: 01/15/2023] Open
Abstract
Background Giardia lamblia is a very common cause of gastrointestinal symptoms worldwide. There are several methods for the diagnosis of Giardia infection, however none are ideal. We aim to find a new, microRNA-based method that will improve the currently available diagnostic methods for giardiasis. Methods Deep-sequence profiling of Giardia small-RNA revealed that miR5 and miR6 are highly expressed in Giardia. These miRNAs were tested by qRT-PCR in duodenal biopsies of patients with giardiasis who were positive by microscopic pathological evaluation. The gastric biopsies of the same patients served as negative control tissues. Additionally, these miRNAs were evaluated in stool samples of patients with proven giardiasis. Results All histologically proven duodenal biopsies of patients with Giardia infection were positive for Giardia miR5, with a mean threshold cycle (Ct) of 23.7, as well as for Giardia DNA qPCR (16S-like gene, mean Ct 26.3). Gastric biopsies which were tested as a control all were negative. Stool evaluation of miR6 in patients with giardiasis showed 90% specificity but only 66% sensitivity, and a lower accuracy rate was obtained with miR5. Conclusion Giardia miR5 testing in duodenal biopsies may be a new method for the diagnosis of giardiasis. It seems to be more sensitive when compared with testing for Giardia DNA by qPCR in duodenal biopsies. It will be important to investigate the contribution of routine Giardia miRNA testing in duodenal biopsies from patients with persistent abdominal symptoms Giardiasis is a major cause of diarrheal disease throughout the world. It is more common in areas with poor sanitation such as in many low-income countries, but it occurs in high-income countries as well. It is the most commonly identified intestinal parasite in the United States and it is endemic in other industrialized countries. The causative agent is the flagellate protozoan Giardia lamblia, and transmission is mainly by the fecal-oral route. The basic method of diagnosis is stool examination. It is usually found through stool microscopy examination which should be performed on fresh stool and repeated in 3 days. Despite some newer diagnostic methods, Giardia is still difficult to detect, often leading to misdiagnoses. In this study we show that using Giardia microRNA (miR5) as a marker for Giardia infection in duodenal biopsies may be a new method for diagnosis of giardiasis. It appears to be more sensitive than histological diagnosis and also more sensitive than Giardia DNA testing in duodenal biopsies. Interestingly, in our patients, duodenal biopsies were done for persistent abdominal symptoms and the finding of Giardia in their biopsy was unexpected. Thus, testing duodenal biopsies for Giardia miRNA in patients with persistent abdominal symptoms might contribute to diagnosis and prompt treatment for those with giardiasis.
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Affiliation(s)
- Tal Meningher
- Laboratory of Molecular Cell Biology, Sheba Medical Center, Ramat Gan, Israel
- Department of Medicine C, Sheba Medical Center, Ramat Gan, Israel
- Molecular Laboratory for the Study of Tropical Diseases, Sheba Medical Center, Ramat Gan, Israel
| | | | - Iris Barshack
- Department of Pathology, Sheba Medical Center, Ramat Gan, Israel
- Faculty of Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Hila Tabibian-Keissar
- Department of Pathology, Sheba Medical Center, Ramat Gan, Israel
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Refael Kohen
- Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot, Israel
| | - Devorah Gur-Wahnon
- Laboratory of Medical Transcriptomics, Nephrology and Hypertension Services, Hadassah—Hebrew University Medical Center, Jerusalem, Israel
| | - Iddo Z. Ben-Dov
- Laboratory of Medical Transcriptomics, Nephrology and Hypertension Services, Hadassah—Hebrew University Medical Center, Jerusalem, Israel
| | - Yechezkel Sidi
- Laboratory of Molecular Cell Biology, Sheba Medical Center, Ramat Gan, Israel
- Department of Medicine C, Sheba Medical Center, Ramat Gan, Israel
- Faculty of Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Dror Avni
- Laboratory of Molecular Cell Biology, Sheba Medical Center, Ramat Gan, Israel
- Department of Medicine C, Sheba Medical Center, Ramat Gan, Israel
- Molecular Laboratory for the Study of Tropical Diseases, Sheba Medical Center, Ramat Gan, Israel
- * E-mail: , (DA); (ES)
| | - Eli Schwartz
- Molecular Laboratory for the Study of Tropical Diseases, Sheba Medical Center, Ramat Gan, Israel
- Faculty of Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
- The Center for Geographic Medicine, Sheba Medical Center, Ramat Gan, Israel
- * E-mail: , (DA); (ES)
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17
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McInally SG, Hagen KD, Nosala C, Williams J, Nguyen K, Booker J, Jones K, Dawson SC. Robust and stable transcriptional repression in Giardia using CRISPRi. Mol Biol Cell 2018; 30:119-130. [PMID: 30379614 PMCID: PMC6337905 DOI: 10.1091/mbc.e18-09-0605] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Giardia lamblia is a binucleate protistan parasite causing significant diarrheal disease worldwide. An inability to target Cas9 to both nuclei, combined with the lack of nonhomologous end joining and markers for positive selection, has stalled the adaptation of CRISPR/Cas9-mediated genetic tools for this widespread parasite. CRISPR interference (CRISPRi) is a modification of the CRISPR/Cas9 system that directs catalytically inactive Cas9 (dCas9) to target loci for stable transcriptional repression. Using a Giardia nuclear localization signal to target dCas9 to both nuclei, we developed efficient and stable CRISPRi-mediated transcriptional repression of exogenous and endogenous genes in Giardia. Specifically, CRISPRi knockdown of kinesin-2a and kinesin-13 causes severe flagellar length defects that mirror defects with morpholino knockdown. Knockdown of the ventral disk MBP protein also causes severe structural defects that are highly prevalent and persist in the population more than 5 d longer than defects associated with transient morpholino-based knockdown. By expressing two guide RNAs in tandem to simultaneously knock down kinesin-13 and MBP, we created a stable dual knockdown strain with both flagellar length and disk defects. The efficiency and simplicity of CRISPRi in polyploid Giardia allows rapid evaluation of knockdown phenotypes and highlights the utility of CRISPRi for emerging model systems.
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Affiliation(s)
- S G McInally
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - K D Hagen
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - C Nosala
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - J Williams
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - K Nguyen
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - J Booker
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - K Jones
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - Scott C Dawson
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
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18
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Missina JM, Gavinho B, Postal K, Santana FS, Valdameri G, de Souza EM, Hughes DL, Ramirez MI, Soares JF, Nunes GG. Effects of Decavanadate Salts with Organic and Inorganic Cations on Escherichia coli, Giardia intestinalis, and Vero Cells. Inorg Chem 2018; 57:11930-11941. [DOI: 10.1021/acs.inorgchem.8b01298] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | | | - Glaucio Valdameri
- Departamento de Análises Clínicas, Universidade Federal do Paraná, Campus Jardim Botânico, Jardim Botânico, 80210-170 Curitiba, Paraná, Brazil
| | | | - David L. Hughes
- School of Chemistry, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Marcel I. Ramirez
- Fundação Osvaldo Cruz, Av. Brazil, Manguinhos, 4365 Rio de Janeiro, Brazil
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19
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Alvarado ME, Rubiano C, Sánchez W, Díaz A, Wasserman M. Calcium-binding proteins that are type B″ regulatory subunits of phosphatase 2A in Giardia intestinalis. Parasitol Res 2018; 117:3205-3214. [PMID: 30043281 DOI: 10.1007/s00436-018-6019-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/17/2018] [Indexed: 10/28/2022]
Abstract
Giardia intestinalis is a protozoan parasite that colonizes the upper part of the small intestine of its mammalian hosts. The trophozoite, which is the replicative stage, has a complex cytoskeleton that allows it to move and adhere to intestinal cells. It has been proposed that protein phosphatase 2A (PP2A) participates in the regulation of changes to the parasite cytoskeleton during its life cycle. However, how PP2A is involved in this regulation remains unclear since its substrates and regulators have not been characterized. In this work, we report the bioinformatic and experimental analysis of two potential regulatory B″ subunits of PP2A in Giardia, both of which are calcium-binding proteins. In this work, in silico and experimental evidence of the binding of both proteins to calcium is presented; the proteins are shown to interact with the catalytic PP2A subunit in the trophozoite stage, and they exhibit different subcellular localization patterns. Because PP2A is a heterotrimer, homology analysis of the different subunits of PP2A indicates that fewer holoenzyme combinations can be formed in this parasite than in other organisms. Our results suggest that the localization of PP2A may be associated with calcium-dependent signaling through its B″ type regulatory subunits.
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Affiliation(s)
- Magda E Alvarado
- Laboratorio de Investigaciones Básicas en Bioquímica - LIBBIQ, Facultad de Ciencias, Universidad Nacional de Colombia, Bogotá, Colombia.
| | - Claudia Rubiano
- Laboratorio de Investigaciones Básicas en Bioquímica - LIBBIQ, Facultad de Ciencias, Universidad Nacional de Colombia, Bogotá, Colombia
| | - William Sánchez
- Laboratorio de Investigaciones Básicas en Bioquímica - LIBBIQ, Facultad de Ciencias, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Andrea Díaz
- Laboratorio de Investigaciones Básicas en Bioquímica - LIBBIQ, Facultad de Ciencias, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Moisés Wasserman
- Laboratorio de Investigaciones Básicas en Bioquímica - LIBBIQ, Facultad de Ciencias, Universidad Nacional de Colombia, Bogotá, Colombia
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20
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Giardia Colonizes and Encysts in High-Density Foci in the Murine Small Intestine. mSphere 2017; 2:mSphere00343-16. [PMID: 28656177 PMCID: PMC5480036 DOI: 10.1128/msphere.00343-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Accepted: 04/21/2017] [Indexed: 01/28/2023] Open
Abstract
Giardia is a single-celled parasite causing significant diarrheal disease in several hundred million people worldwide. Due to limited access to the site of infection in the gastrointestinal tract, our understanding of the dynamics of Giardia infections in the host has remained limited and largely inferred from laboratory culture. To better understand Giardia physiology and colonization in the host, we developed imaging methods to quantify Giardia expressing bioluminescent physiological reporters in two relevant animal models. We discovered that parasites primarily colonize and encyst in the proximal small intestine in discrete, high-density foci. We also show that high parasite density contributes to encystation initiation. Giardia lamblia is a highly prevalent yet understudied protistan parasite causing significant diarrheal disease worldwide. Hosts ingest Giardia cysts from contaminated sources. In the gastrointestinal tract, cysts excyst to become motile trophozoites, colonizing and attaching to the gut epithelium. Trophozoites later differentiate into infectious cysts that are excreted and contaminate the environment. Due to the limited accessibility of the gut, the temporospatial dynamics of giardiasis in the host are largely inferred from laboratory culture and thus may not mirror Giardia physiology in the host. Here, we have developed bioluminescent imaging (BLI) to directly interrogate and quantify the in vivo temporospatial dynamics of Giardia infection, thereby providing an improved murine model to evaluate anti-Giardia drugs. Using BLI, we determined that parasites primarily colonize the proximal small intestine nonuniformly in high-density foci. By imaging encystation-specific bioreporters, we show that encystation initiates shortly after inoculation and continues throughout the duration of infection. Encystation also initiates in high-density foci in the proximal small intestine, and high density contributes to the initiation of encystation in laboratory culture. We suggest that these high-density in vivo foci of colonizing and encysting Giardia likely result in localized disruption to the epithelium. This more accurate visualization of giardiasis redefines the dynamics of the in vivo Giardia life cycle, paving the way for future mechanistic studies of density-dependent parasitic processes in the host. IMPORTANCEGiardia is a single-celled parasite causing significant diarrheal disease in several hundred million people worldwide. Due to limited access to the site of infection in the gastrointestinal tract, our understanding of the dynamics of Giardia infections in the host has remained limited and largely inferred from laboratory culture. To better understand Giardia physiology and colonization in the host, we developed imaging methods to quantify Giardia expressing bioluminescent physiological reporters in two relevant animal models. We discovered that parasites primarily colonize and encyst in the proximal small intestine in discrete, high-density foci. We also show that high parasite density contributes to encystation initiation.
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21
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Pham JK, Nosala C, Scott EY, Nguyen KF, Hagen KD, Starcevich HN, Dawson SC. Transcriptomic Profiling of High-Density Giardia Foci Encysting in the Murine Proximal Intestine. Front Cell Infect Microbiol 2017; 7:227. [PMID: 28620589 PMCID: PMC5450421 DOI: 10.3389/fcimb.2017.00227] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/16/2017] [Indexed: 12/15/2022] Open
Abstract
Giardia is a highly prevalent, understudied protistan parasite causing significant diarrheal disease worldwide. Its life cycle consists of two stages: infectious cysts ingested from contaminated food or water sources, and motile trophozoites that colonize and attach to the gut epithelium, later encysting to form new cysts that are excreted into the environment. Current understanding of parasite physiology in the host is largely inferred from transcriptomic studies using Giardia grown axenically or in co-culture with mammalian cell lines. The dearth of information about the diversity of host-parasite interactions occurring within distinct regions of the gastrointestinal tract has been exacerbated by a lack of methods to directly and non-invasively interrogate disease progression and parasite physiology in live animal hosts. By visualizing Giardia infections in the mouse gastrointestinal tract using bioluminescent imaging (BLI) of tagged parasites, we recently showed that parasites colonize the gut in high-density foci. Encystation is initiated in these foci throughout the entire course of infection, yet how the physiology of parasites within high-density foci in the host gut differs from that of cells in laboratory culture is unclear. Here we use BLI to precisely select parasite samples from high-density foci in the proximal intestine to interrogate in vivo Giardia gene expression in the host. Relative to axenic culture, we noted significantly higher expression (>10-fold) of oxidative stress, membrane transporter, and metabolic and structural genes associated with encystation in the high-density foci. These differences in gene expression within parasite foci in the host may reflect physiological changes associated with high-density growth in localized regions of the gut. We also identified and verified six novel cyst-specific proteins, including new components of the cyst wall that were highly expressed in these foci. Our in vivo transcriptome data support an emerging view that parasites encyst early in localized regions in the gut, possibly as a consequence of nutrient limitation, and also impact local metabolism and physiology.
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Affiliation(s)
- Jonathan K Pham
- Department of Microbiology and Molecular Genetics, University of California, DavisDavis, CA, United States
| | - Christopher Nosala
- Department of Microbiology and Molecular Genetics, University of California, DavisDavis, CA, United States
| | - Erica Y Scott
- Department of Animal Science, University of California, DavisDavis, CA, United States
| | - Kristofer F Nguyen
- Department of Microbiology and Molecular Genetics, University of California, DavisDavis, CA, United States
| | - Kari D Hagen
- Department of Microbiology and Molecular Genetics, University of California, DavisDavis, CA, United States
| | - Hannah N Starcevich
- Department of Microbiology and Molecular Genetics, University of California, DavisDavis, CA, United States
| | - Scott C Dawson
- Department of Microbiology and Molecular Genetics, University of California, DavisDavis, CA, United States
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22
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Divergent Transcriptional Responses to Physiological and Xenobiotic Stress in Giardia duodenalis. Antimicrob Agents Chemother 2016; 60:6034-45. [PMID: 27458219 DOI: 10.1128/aac.00977-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 07/19/2016] [Indexed: 12/22/2022] Open
Abstract
Understanding how parasites respond to stress can help to identify essential biological processes. Giardia duodenalis is a parasitic protist that infects the human gastrointestinal tract and causes 200 to 300 million cases of diarrhea annually. Metronidazole, a major antigiardial drug, is thought to cause oxidative damage within the infective trophozoite form. However, treatment efficacy is suboptimal, due partly to metronidazole-resistant infections. To elucidate conserved and stress-specific responses, we calibrated sublethal metronidazole, hydrogen peroxide, and thermal stresses to exert approximately equal pressure on trophozoite growth and compared transcriptional responses after 24 h of exposure. We identified 252 genes that were differentially transcribed in response to all three stressors, including glycolytic and DNA repair enzymes, a mitogen-activated protein (MAP) kinase, high-cysteine membrane proteins, flavin adenine dinucleotide (FAD) synthetase, and histone modification enzymes. Transcriptional responses appeared to diverge according to physiological or xenobiotic stress. Downregulation of the antioxidant system and α-giardins was observed only under metronidazole-induced stress, whereas upregulation of GARP-like transcription factors and their subordinate genes was observed in response to hydrogen peroxide and thermal stressors. Limited evidence was found in support of stress-specific response elements upstream of differentially transcribed genes; however, antisense derepression and differential regulation of RNA interference machinery suggest multiple epigenetic mechanisms of transcriptional control.
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